Growth in Germany Lost Momentum in August While French Factories Continue to Struggle

LONDON—Business activity in the euro zone slowed in August, held back by weakening factory output in its two biggest economies.

Financial data firm Markit said Thursday its purchasing managers' index for the euro zone, a closely watched gauge of private-sector activity, weakened in August to 52.8 from 53.8 in July. A reading above 50 indicates...